Acute kidney failure

Acute (sudden) kidney failure is the sudden loss of the ability of the kidneys to remove waste and concentrate urine without losing electrolytes.

Causes, incidence, and risk factors

There are many possible causes of kidney damage. They include:

Acute tubular necrosis (ATN)

Autoimmune kidney disease, including:

Acute nephritic syndrome

Interstitial nephritis

Decreased blood flow due to very low blood pressure, which can result from:

Burns

Dehydration

Hemorrhage

Injury

Septic shock

Serious illness

Surgery

Disorders that cause clotting within the kidney's blood vessels:

Hemolytic-uremic syndrome

Idiopathic thrombocytopenic thrombotic purpura (ITTP)

Malignant hypertension

Transfusion reaction

Scleroderma

Infections that directly injure the kidney, such as:

Acute pyelonephritis

Septicemia

Pregnancy complications, including:

Placenta abruptio

Placenta previa

Urinary tract obstruction

Symptoms

Bloody stools

Breath odor

Bruising easily

Changes in mental status or mood

Decreased appetite

Decreased sensation, especially in the hands or feet

Fatigue

Flank pain (between the ribs and hips)

Hand tremor

High blood pressure

Metallic taste in mouth

Nausea or vomiting, may last for days

Nosebleeds

Persistent hiccups

Prolonged bleeding

Seizures

Slow, sluggish movements

Swelling - generalized (fluid retention)

Swelling of the ankle, foot, and leg

Urination changes:

Decrease in amount of urine

Excessive urination at night

Urination stops completely

Signs and tests

Many patients have generalized swelling caused by fluid retention. The doctor may hear a heart murmur, crackles in the lungs, or signs of inflammation of the lining of the heart when listening to the heart and lungs with a stethoscope.

The results of laboratory tests may change suddenly (within a few days to 2 weeks). Such tests may include:

BUN

Creatinine clearance

Serum creatinine

Serum potassium

Urinalysis

A kidney or abdominal ultrasound is the preferred test for diagnosing kidney failure, but abdominal x-ray, abdominal CT scan, or abdominal MRI can tell if there is a blockage in the urinary tract.

Blood tests may help reveal the underlying cause of kidney failure. Arterial blood gas and blood chemistries may show metabolic acidosis.

Treatment

Once the cause is found, the goal of treatment is to restore kidney function and prevent fluid and waste from building up in the body while the kidneys heal. Usually, you have to stay overnight in the hospital for treatment.

The amount of liquid you eat (such as soup) or drink will be limited to the amount of urine you can produce. You will be told what you may and may not eat to reduce the buildup of toxins normally handled by the kidneys. Your diet may need to be high in carbohydrates and low in protein, salt, and potassium.

You may need antibiotics to treat or prevent infection. Diuretics ("water pills") may be used to help the kidneys lose fluid.

Calcium or glucose/insulin will be given through a vein to help avoid dangerous increases in blood potassium levels.

Dialysis may be needed, and can make you feel better. It is not always necessary, but it can save your life if your potassium levels are dangerously high. Dialysis will also be used if your mental status changes, you stop urinating, develop pericarditis, retain too much fluid, or cannot eliminate nitrogen waste products from your body.

Support Groups

The stress of having an illness can often be helped by joining a support group where members share common experiences and problems.

See: Kidney disease - support group

Expectations (prognosis)

Acute kidney failure is potentially life-threatening and may require intensive treatment. However, the kidneys usually start working again within several weeks to months after the underlying cause has been treated.

In some cases, chronic renal failure or end-stage renal disease may develop. Death is most common when kidney failure is caused by surgery, trauma, or severe infection in someone with heart disease, lung disease, or recent stroke. Old age, infection, loss of blood from the intestinal tract, and progression of kidney failure also increase the risk of death.

Complications

Chronic (long-term) kidney failure

Damage to the heart or nervous system

End-stage kidney disease

High blood pressure

Loss of blood in the intestines

Calling your health care provider

Call your health care provider if your urine output slows or stops or you have other symptoms of acute kidney failure.

Prevention

Treating disorders such as high blood pressure can help prevent acute kidney failure.